1. Field of the Invention
The invention relates in general to a signal delivering apparatus, and more particularly to an apparatus for delivering the power status data signal indicative of the power status of a smart battery.
2. Description of the Related Art
Portable computers are commonly called notebook computers, which are easy for carriage. Without an outer power source, the portable computer uses its battery as the only power source. Therefore, keeping the portable computer supplied with steady power by the battery is a very important issue to the operation of the portable computer system.
Currently, the type of battery device used in the portable computer is smart battery device. It can provide the power status data signal indicative of the power status of the battery to the system central processing unit (system CPU) of the portable computer system through the bus between the system and the battery. Therefore, the system CPU can carry out the power management task according to the power status data of the smart battery device. For example, if a user does not give any command through the keyboard or other peripheral input/output device for a long period of time, the system CPU can shut down the operation of the monitor, hard disk or other apparatus to reduce the power consumption. When the power in the battery is consumed under a certain amount, the system CPU can lower the luminance of the monitor, or deliver a warning message to inform the user that the battery needs to be recharged. Further, when the power stored in the battery runs out, the system CPU can suspend current data to the memory, or to the hard disk and then shut down the whole computer system.
In the portable computer, an embedded controller is in charge of delivering the power status data signal of the smart battery. The system CPU commands the embedded controller to provide the power status data signal of the smart battery to the system CPU regularly. After receiving the power status data from the embedded controller, the system CPU will carry out the power management task according to the power status of the battery device.
However, the embedded controller still has to do other tasks in addition to delivering the power status data signal of the smart battery. For example, the embedded controller has to deliver signals from keyboard or other peripheral input device, or control play of the CD drive. Because the system CPU commands the embedded controller to read the power status data of the smart battery regularly, the embedded controller has to regularly interrupt the task being executed, in order to deliver the power status data of the smart battery. Thus, it has a negative effect upon the performance and efficiency of the embedded controller in executing other tasks. Besides, it takes time for the embedded controller to deliver the power status data of the smart battery to the system CPU through the bus. When the system CPU commands the embedded controller to read the power status data of the smart battery, the system CPU has to regularly interrupt the task being executed to wait for the power status data that is provided by the embedded controller. Therefore, it also has a negative effect upon the performance and efficiency of the system CPU in executing other tasks.
The conventional method to improve the delivery of the power status data of the smart battery is to assign a memory block of the basic input/output system (BIOS) to store the power status data. The embedded controller delivers the power status data to the assigned memory block of the basic input/output system instead of delivering to the system CPU directly. The assigned memory block of the basic input/output system stores the power status data. When needed, the system CPU can get the power status data from the assigned memory of the basic input/output system regularly. Therefore, it can reduce the waiting time of the system CPU. The system CPU does not need to interrupt the task being executed to receive the power status data of the smart battery regularly.
When the system CPU reads the power status data signal of the smart battery according to the prior art, there are some disadvantages still. First, the embedded controller still has to interrupt the task being executed so as to deliver the power status data of the smart battery regularly when it is commanded by the system CPU. This still has a negative effect upon the performance and efficiency of the embedded controller in executing other tasks. Second, it takes time for the basic input/output system to get the power status data from the embedded controller and store it to the assigned memory block. The above-mentioned method does not reduce time on delivering the power status data from the embedded controller to the basic input/output system. Third, the embedded controller is substantially a central processing unit (CPU). By designing complicated command sets in the embedded controller, the embedded controller is capable of performing more complicated functions than that of the common logic circuit. Therefore, the embedded controller is much more expensive than the common logic circuit. Therefore, it is unnecessary to use such complicated embedded controller to deliver the power status data of the smart battery. Instead of the embedded controller, the power status data can be delivered by properly designed logic devices.
In brief, the conventional method to deliver the state of charge of the smart battery has the following disadvantages. First, it has negative effects upon the performance and efficiency of the embedded controller for other tasks. Second, it takes a long time to store the power status data into the basic input/output system. Third, it is not economical to use the embedded controller to carry out the delivery of the power status data of the smart battery.